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Warmup: Concept: OHM’s Law Electrical current is a measure of the rate at which electrical charge moves in a circuit. Electrical current is measured in AMPERES. 1 Ampere is equal to 1 unit of electrical charge (6.25x1018 electrons!) moving through a circuit in 1 second. Electrical resistance is measured in Ohms. Electrical resistance is caused by electrons bumping into atoms as the electrons try to move on a wire conductor. Electrical resistance is sort of like electrical friction, it creates waste heat. Voltage is electrical force. Voltage is caused by a difference in charge between two points in a circuit. Voltage is the force that moves electrons in a circuit. Voltage is measured in volts. OHM’s LAW: V=I•R V=I•R In this equation “V” is voltage measured in volts, “I” is electrical current measured in Amperes, and “R” is electrical resistance measured in Ohm’s. Q: What is the current in a circuit that has a resistance of 300Ω and a voltage of 16.0V? I=V/R I= 16V/300Ω I= .05A The current is .05 Amperes http://www.ndt-ed.org/EducationResources/HighSchool/Electricity/ohmslaw.htm